Miniature cameras are well known. Miniature cameras are widely used in contemporary cellular telephones. They are also used in other personal electronic devices, such as laptop computers and personal digital assistants (PDAs). Miniature cameras can additionally be used as stand alone devices for such applications as security and surveillance
It is generally desirable to minimize the size of a camera used in cellular telephones and the like. This is due to the ongoing reduction in size of the cellular telephone itself. It is also due to the desire to provide other features. All of the features of a contemporary cellular telephone, including the camera, compete for space within the cellular telephone.
Reducing the size of a camera for a cellular telephone includes reducing the size of the optics for the camera. Indeed, the optics can contribute substantially to the overall size of the camera. Thus, reducing the size of the optics can have a substantial impact upon the overall size of the camera.
The size of the optics can be reduced by reducing the length and/or the diameter of the optics. One prior art attempt at reducing the length of the optics has been to reduce the number of optical elements. Generally, four lenses are provided in miniature cameras for cellular telephones and the like. By reducing the number of lenses to three, the length of the optics can be correspondingly reduced.
However, four lenses are necessary to limit distortion, such as pincushion and barrel. Four lenses are also necessary in order to provide desired resolution, such as that measured by the modulation transfer function (MTF).
Reducing the diameter of the optics requires reducing the size of the clear aperture of the lens or lenses thereof. However, reducing the size of the clear aperture while minimizing any adverse impact upon distortion and/or resolution is difficult.
Thus, although such contemporary attempts at reducing the size of miniature camera optics have proven somewhat useful for their intended purposes, these attempts possess inherent deficiencies which detract from their overall effectiveness and desirability. In view of these deficiencies, it is desirable to provide optics for miniature cameras, wherein the optics are reduced in size so as to facilitate use of the miniature cameras in cellular telephones and the like.